/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.alibaba.nacos.config.server.service.datasource;

import com.alibaba.nacos.config.server.utils.PropertyUtil;
import org.springframework.stereotype.Component;

/**
 * Datasource adapter.
 *
 * @author Nacos
 */
@Component
public class DynamicDataSource {

	private DataSourceService localDataSourceService = null;

	private DataSourceService basicDataSourceService = null;

	private static final DynamicDataSource INSTANCE = new DynamicDataSource();

	public static DynamicDataSource getInstance() {
		return INSTANCE;
	}

	public synchronized DataSourceService getDataSource() {
		try {

			// Embedded storage is used by default in stand-alone mode
			// In cluster mode, external databases are used by default

			if (PropertyUtil.isEmbeddedStorageX()) {
				if (localDataSourceService == null) {
					localDataSourceService = new LocalDataSourceServiceImpl();
					localDataSourceService.init();
				}
				return localDataSourceService;
			} else {
				if (basicDataSourceService == null) {
					basicDataSourceService = new ExternalDataSourceServiceImpl();
					basicDataSourceService.init();
				}
				return basicDataSourceService;
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

}
